Within the integrated circuit industry there is a continuing effort to increase integrated circuit device density and speed. As integrated circuits become smaller, the number of interconnections and the amount of heat generated per square inch may increase accordingly. Increased heating of an integrated circuit device may affect the performance of the device and may cause permanent damage. Further, electromagnetic emissions may also increase with faster switching speeds which may increase the need for shielding to prevent electromagnetic interference (EMI) to adjacent or nearby devices and equipment. Semiconductor packages may be designed to address some of these issues.
For example, a flip chip package, also known as control collapse chip connection (C4) package, may accommodate interconnection requirements of high-density integrated circuits. In a typical flip chip package, an integrated circuit (a chip) may be mounted to the top surface of a package substrate that serves as an interconnection device. The package substrate typically consists of top and bottom surface buildup layers of interconnect circuitry disposed on a substrate core. As current is passed through the top and bottom buildup layers, heat may be generated, which may cause the package substrate to self-heat. The substrate core is typically made of an organic material that is not thermally conductive, and so acts as a thermal insulator to the buildup layer.
A current solution to remove heat from a flip chip package is to attach a heat spreader in thermal contact with a backside surface of the integrated circuit. The heat spreader is typically attached to a solder area around the perimeter of the top buildup layers. Because the solder resist area is not thermally conductive, there may be no path for heat transfer from a self-heated package substrate to the heat spreader. Therefore, the heat spreader may do little to remove heat from the self-heated package substrate. Further, because the solder resist area is not electrically conductive, the heat spreader may not be grounded and may not provide adequate EMI suppression.